Retinal implants to help pilots see at night, stimulant drugs to keep surgeons alert and steady handed, cognitive enhancers to focus the minds of executives for a big speech or presentation.

Medical and scientific advances are bringing human enhancements into work but with them, according to a report by British experts, come not only the potential to help society and boost productivity, but also a range of ethical dilemmas.

"We're not talking science fiction here, we're talking about advances that could impact significantly on the way we work...in the near future," said Genevra Richardson, a professor of law at Kings College London and one of the authors of the report.

The report was published after a joint workshop involving four major British scientific institutions which looked at emerging technologies like cognitive enhancing drugs, bionic limbs and retinal implants that have the potential to change workplaces dramatically in future.

Richardson said while such developments may benefit society in important ways, such as by boosting workforce productivity, their use also had "significant policy implications" to be considered by governments, employers, workers and trades unions.

"There are a range of technologies in development and in some cases already in use that have the potential to transform our workplaces - for better or for worse," she said.

Human physical and cognitive enhancements are primarily developed with sick or disabled people in mind, as medicines or therapies to help them overcome mental or physical disorders.

But experts say drugs and other forms of enhancement are being used increasingly by healthy people who want to benefit from the boost they can give to performance.

Barbara Sahakian, a professor of clinical neuropsychology at Cambridge University who contributed to the report, said for example that modafinil, a generic drug prescribed for sleep disorders such as narcolepsy, is often used by academics or business leaders travelling to conferences who need to be at the top of their game when delivering a speech.

"They take (sleep) medications on the plane to fall asleep, and take modafinil to wake up when they get there," she said.

Other stimulants such as Novartis's Ritalin and Shire's Adderall, prescribed for conditions like Attention Deficit Hyperactivity Disorder, are also used by healthy people to increase focus.

One issue with this kind of use is the lack of long-term safety studies of such drugs in healthy people, the experts said, so there may be unknown risks ahead. Other problems include whether cognitive enhancers are fair. Is it cheating to go into a job interview or exam having taken a drug to boost your mental focus?

Research from the Massachusetts College of Liberal Arts in the United States has estimated that up to 16 percent of students in America also use cognitive enhancers to improve performance in exams or for particular essays or projects.

The report also pointed to visual enhancement technologies, such as retinal implants, that could be used by the military, by night watchmen, safety inspectors or gamekeepers.

Technologies to enhance night vision or extend of the range of human vision to include other wavelengths such as ultra-violet light could become a reality relatively soon, it said.

Sahakian suggested that for drivers or pilots, such enhancements could reduce fatigue and lower the risk of fatal accidents.

But she also raised the question of whether employers keen to squeeze more productivity out of a workforce might coerce workers into using enhancements against their will.

"Imagine you're a bus driver bringing children back on a journey to the UK overnight and your boss says you have to take cognitive-enhancing drug because there are risks to the children if you don't stay awake. Is that acceptable?," she said. "These are the kinds of things we have to grapple with."